mcf51mm256 Freescale Semiconductor, Inc, mcf51mm256 Datasheet - Page 34

• Manufacturer Part Number: mcf51mm256
• Description: 32-bit Coldfire V1 Central Processor Unit
• Manufacturer: Freescale Semiconductor, Inc

Preliminary Electrical Characteristics
1
2
3
4
5
6
7
34
10
11 Lock frequency tolerance
12 Lock time
13
14
#
7
8 VCO operating frequency
9 PLL reference frequency range
This should not exceed the maximum CPU frequency for this device.
This specification applies to any time the FLL reference source or reference divider is changed, trim value is changed, DMX32 bit is
changed, DRS bit is changed, or changing from FLL disabled (BLPE, BLPI) to FLL enabled (FEI, FEE, FBE, FBI). If a crystal/resonator is
being used as the reference, this specification assumes it is already running.
This specification applies to any time the PLL VCO divider or reference divider is changed, or changing from PLL disabled (BLPE, BLPI)
to PLL enabled (PBE, PEE). If a crystal/resonator is being used as the reference, this specification assumes it is already running.
Jitter is the average deviation from the programmed frequency measured over the specified interval at maximum f
made with the device powered by filtered supplies and clocked by a stable external clock signal. Noise injected into the FLL circuitry via
V
625 ns represents 5 time quanta for CAN applications, under worst-case conditions of 8 MHz CAN bus clock, 1 Mbps CAN Bus speed, and
8 time quanta per bit for bit time settings. 5 time quanta is the minimum time between a synchronization edge and the sample point of a bit
using 8 time quanta per bit.
Below D
in lock, then the MCG may stay in lock.
Below D
DD
Long term Jitter of DCO output clock (averaged over 2mS
interval)
Jitter of PLL output clock measured
over 625ns
Loss of external clock minimum frequency - RANGE = 0
Loss of external clock minimum frequency - RANGE = 1
and V
lock
unl
SS
minimum, the MCG will not exit lock if already in lock. Above D
minimum, the MCG is guaranteed to enter lock. Above D
4
and variation in crystal oscillator frequency increase the C
5
Table 17. MCG (Temperature Range = –40 to 105
Rating
Long term
Entry
Exit
FLL
PLL
7
6
lock
f
pll_jitter_625
Jitter
Symbol
maximum, the MCG will not enter lock. But if the MCG is already
f
t
f
t
loc_high
C
f
pll_lock
loc_low
fll_lock
unl
D
pll_ref
D
f
Jitter
vco
ns
lock
unl
percentage for a given interval.
maximum, the MCG is guaranteed to exit lock.
°
C Ambient) (continued)
(16/5) x
(3/5) x
± 1.49
± 4.47
Min
f
f
7.0
1.0
int_t
int_t
—
—
—
—
Typical
0.566
0.02
—
—
—
—
—
—
—
—
4
1075(1/
1075(1/
t
t
pll_acquire+
fll_acquire+
± 2.98
± 5.97
Freescale Semiconductor
Max
55.0
0.2
2.0
BUS
—
—
—
f
f
pll_ref)
int_t)
. Measurements are
%f
MHz
MHz
Unit
%f
kHz
kHz
%
s
dco
pll
C
C
D
D
D
D
D
D
D
D
D